Cross-recognition of N-formylmethionine peptides is a general characteristic of H2-M3-restricted CD8+ T cells.

Infectious Diseases Service, Department of Medicine and Laboratory of Antimicrobial Immunity, Immunology Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York 10021, USA.
Infection and Immunity (Impact Factor: 4.16). 08/2005; 73(7):4423-6. DOI: 10.1128/IAI.73.7.4423-4426.2005
Source: PubMed

ABSTRACT H2-M3-restricted CD8+ T cells can exhibit cross-reactivity to different bacterially derived N-formylmethionine peptides. The extent of this promiscuity is unclear. We deleted the nonredundant fMIVTLF epitope and found that Listeria monocytogenes still primed fMIVTLF-specific T cells. Thus, cross-reactivity appears to be a more general characteristic of H2-M3-restricted T cells.

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    ABSTRACT: The major histocompatibility complex (MHC) class Ib molecule H2-M3 primes the rapid expansion of CD8+ T cells by presenting N-formylated bacterial peptides. However, the signifi cance of H2-M3-restricted T cells in host defense against bacteria is unclear. We generated H2-M3-defi cient mice to investigate the role of H2-M3 in immunity against Listeria monocytogenes (LM), a model intracellular bacterial pathogen. H2-M3-defi cient mice are impaired in early bacterial clearance during primary infection, with diminished LM-specifi c CD8+ T cell responses and compromised innate immune functions. Although H2-M3-restricted CD8+ T cells constitute a signifi cant proportion of the anti-listerial CD8+ T cell repertoire, the kinetics and magnitude of MHC class Ia-restricted T cell responses are not altered in H2-M3-defi cient mice. The fact that MHC class Ia-restricted responses cannot compensate for the H2-M3-mediated immunity suggests a nonredundant role of H2-M3 in the protective immunity against LM. Thus, the early H2-M3-restricted response temporally bridges the gap between innate and adaptive immune responses, subsequently affecting the function of both branches of the immune system.


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